Saprolegnia infections of salmonid fish

This paper deals firstly with the identification and characteristics of fungal pathogens that colonize salmonids and then considers the relative importance of the condition of the host fish and the environmental factors which may influence the interaction between pathogen and host.

Pathology of mixed infections of saprolegniasis-myxosporidiosis in Indian major carp (Catla catla Ham.)

An outbreak of saprolegniasis in Catla catla in composite carp culture ponds were recorded during winter season. The typical cotton wool growths were observed on whole body surfaces of catla along with sporadic mortality. The fungal invasion was only restricted to skin and no fungal elements were visible in any internal organs after periodic acid schiff staining. On histology, periportal accumulation of mononuclear cells in liver, presence of myxosporidean cysts in antieror kidney, eosinophilic granular cells reaction in submucosa of stomach and intestine, dilated and engorged blood vessels of brain along with sloughing of epidermis and hyperplasia at gill lamellar base were pronounced changes. The possible role of release of Saprolegnia toxin in producing internal organs pathology has been discussed.

Natural Suppression of the Aquatic Weed Salvinia molesta D.S. Mitchell, by Two Previously Unreported Fungal Pathogens

Salvinia molesta D. S. Mitchell (Salviniaceae), variously called giant salvinia, water fern or African payal, is a vegetatively reproducing, perennial, free-floating, aquatic weed, native to southeastern Brazil (Waterhouse and Norris 1987). It (hereafter called salvinia) is a very serious weed in most regions outside its native range (Harley and Mitchell 1981) including India. The purpose of this paper is to report on two fungal pathogens that were found to be the cause of a sudden decline in salvinia in Bangalore.(PDF has 4 pages.)

Survey of fungal infestation of some fish species from Tagwai dam, Minna, Niger State

Survey of Fungal infestation of some species of fish in Tagwai Dam Minna was carried out from March to June 2002. Fungi were isolated from the scale/skin, gills and fins. Twenty-one fungi species were identified from 18 species of fish microbial growth was measured by direct cell count using Stuart colony counter. Most of the fungi encountered were of the mould group and infestation occurred among all the species sampled. The infestation was predominantly by Aspergillus species and the scale/skin was most widely affected. The study showed the identified fungi in order of frequency to be as follows. Aspergillius niger. Rrhizopus spp. Mmucor spp Aspergilus flavum. Aspergillus parasitous. Aspergillus fumigatus, Microsporum canis. Penicillum virridicalumand Fusarium spp respectively. Aspergillus niger occurred on all the species of fish sampled. Barrilius spa and Chrysichrhy auratus longifilis had significantly higher (P<0.05) mean fungal load on their fins and gills. There was no significant difference (P>0.05) in the mean fungal load in different parts of the body of other fish species sampled

Investigation of nematode Eustrongylides larvae infections in mudfish Clarias gariepinus and C. anguillaris from Bida floodplain of Nigeria

This is the first report and record of the determination whether mudfish Clarias were infected with the larvae of the nematode Eustrongylides. Also, documented the assessment of the socio-economic perceptions of three groups of fisher folks on the economy of infected mudfish Clarias fishing activities. Fifty-six (67.5%) of 83 mudfish Clarias caught by artisanal fisher folks were examined for the presence of the larvae of the nematode Eustrongylides. All the 8 sampled fishing localities in Bida floodplain of Nigeria had a mean intensity and abundance of at least 3 and 1 worm per fish per site, respectively. Two hundred and one (96.2%) of 209 worms recovered were from the musculatures at different depths resulting in undulations on the skin surfaces as grub-like presentations. The three groups of fisher folks assessed encountered economic losses from nematode infected mudfish Clarias which attract much debates or rejections during marketing due to its aesthetically displeasing appearance, faster deterioration, higher fragility in smoked form coupled with poorer taste compared to the wholesome ones. Infected female mudfish Clarias had higher worm burden than the males, for each fishing locality

Fungal and protozoan parasites and their importance in the ecology of the phytoplankton

The presence of fungi on the phytoplankton of Lake Windermere was first noted by the author in 1943. Surveys into the fungal and protozoan parasites of the planktonic algae of the English Lake District and elsewhere were carried out. This article discusses the descriptive studies, epidemics and culture work, which was carried out in connection with these studies.

Removal of fungus and prevention of fungal reinfestation in stored dry salted fish

A simple and effective method is described for converting dry fish products infested with fungus and red halophilic bacteria to acceptable ones. Washing, drying and then smearing with a mixture of 3% sodium propionate in dry, refined salt in a ratio of 1 part mixture: 10 parts dry fish resulted in the fish having a shelf life of 5 months.

Studies on the probable sources of fungal infection and the control measures in a fish seed farm

The causes of mortality of fry of cultivable fishes in a fish seed farm were investigated. The mortality was due to fungal infection and the pathogen was Saprolegnia sp. The sources of infection were unhygienic breeding hapas, spawnery hapas in the cemented ponds, hatching jars and excess feeding. Application of one kg slaked lime followed by 75g of CuSo sub(4)(l-0.5 p.p.m.) and 150g of KMno sub(4)(2-1 p.p.m.) per each nursery (158m³ water) controlled the pathogen.

Some fungal infestations of dried fishes in Cochin markets

Dried fish constitutes a regular item of trade in India, particularly in the interior parts far away from the sea and rivers. The poor section of the society is the main consumer. The quality of dried fish never receives much attention at any stage of processing (drying) and storage. A good amount of these fish is discarded during drying due to fungal growth to avoid the danger of mycotoxin production. A survey of the dried fish from the Cochin markets had revealed that they do carry fungal infestations and their chances of mycotoxin production cannot be ruled out as the strains of Aspergillus flavus, Aspergillus ochraceus and Fusarium spp. have been isolated.

Studies on the fungal diseases in crustaceans. I. Lagenidum scyllae sp. nov. isolated from cultivated ova and larvae of the mangrove crab (Scylla serrata)

Lagenidium scyllae , a marine mastigomycete from the ova and larvae of the mangrove crab, is described and illustrated as new. The fungus grew at a temperature range of 16-42 C, with an optimum at 22.5-31.8 C. It grew well in peptone-yeast-glucose (PYG) broth containing 2-3% NaCl. In PYG-sea water medium, it grew at a pH range of 5-11.

Evaluation and comparison of ozone, hydrogen peroxide and physical treatment on fungal infection prevention and hatching rate of Iranian sturgeon (Acipenser persicus)

Ozone due to having low half-life and devoid of environmental harmful effects is recognized as one of the most effective disinfectant and fungicide in aquaculture. The objective of this study is to consider the effects of periodicay ozonation, hydrogen peroxide treatment, and physical treatment capability in hatching rate enhancement. Three concentrations of 0.05, 0.1 and 0.15 ppm ozone (10 min) and peroxide hydrogen with dose of 500 and 1000 ppm in two procedures accompanied with physical treatment and without physical treatment were examined on hatching rate. In the first year, Egg ozonation (0.1 ppm) with physical treatment have been resulted the greatest hatching rate (81.4%). In the second year, egg treatment with 1000 ppm hydrogen peroxide with physical treatment have been showed the greatest hatching rate (78%). Average hatching rate for the blank control treatment (without disinfectin and physical treatment) was 32.7%. From the economic viewpoint, 0.05 ppm ozone with physical treatment, due to considerable minimizing at consumption energy and ozonation system retention costs, indicated as the best treatment than other ozone treatments for fungal control. Very low correlation (r=-0.14) have been observed between hatchery water temperature and fungal infection percentage in control treatment.